[PATCH 9/9] Documentation: update api-builtin and api-setup

["Nguyễn Thái Ngọc Duy" <pclouds@gmail.com>]

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
---
 Documentation/technical/api-builtin.txt |   10 ++++
 Documentation/technical/api-setup.txt   |   70 +++++++++++++++++++++++++++----
 2 files changed, 72 insertions(+), 8 deletions(-)

diff --git a/Documentation/technical/api-builtin.txt b/Documentation/technical/api-builtin.txt
index 52cdb4c..f0d988b 100644
--- a/Documentation/technical/api-builtin.txt
+++ b/Documentation/technical/api-builtin.txt
@@ -33,6 +33,10 @@ git:
 	If the standard output is connected to a tty, spawn a pager and
 	feed our output to it.
 
+`NEED_WORK_TREE`::
+
+	Make sure there is a work tree to work on.
+
 . Add `builtin-foo.o` to `BUILTIN_OBJS` in `Makefile`.
 
 Additionally, if `foo` is a new command, there are 3 more things to do:
@@ -59,5 +63,11 @@ to the subdirectory the command started from.  This allows you to
 convert a user-supplied pathname (typically relative to that directory)
 to a pathname relative to the top of the work tree.
 
+`NEED_WORK_TREE` also set `prefix` like `RUN_SETUP`. But it will `die()`
+if there is no work tree.
+
+If neither `NEED_WORK_TREE` nor `RUN_SETUP` is set, `prefix` is always `NULL`.
+No chdir(2) will be done.
+
 The return value from `cmd_foo()` becomes the exit status of the
 command.
diff --git a/Documentation/technical/api-setup.txt b/Documentation/technical/api-setup.txt
index 4f63a04..43e5a81 100644
--- a/Documentation/technical/api-setup.txt
+++ b/Documentation/technical/api-setup.txt
@@ -1,13 +1,67 @@
 setup API
 =========
 
-Talk about
+End-user point-of-view how the setup works
+------------------------------------------
 
-* setup_git_directory()
-* setup_git_directory_gently()
-* is_inside_git_dir()
-* is_inside_work_tree()
-* setup_work_tree()
-* get_pathspec()
+. If you have `GIT_DIR` exported, then no discovery is attempted.
+  We use the `GIT_DIR` you set it, and the repository lives
+  there.  `$GIT_DIR/config` is the repository config.
 
-(Dscho)
+. Otherwise we do the usual discovery going up to find the
+  repository.
+
+. If you have `GIT_WORK_TREE` exported, or otherwise if the
+  config has `core.worktree`, that's where your worktree is.
+  If these variables point to an invalid place, you have no worktree.
+
+. Otherwise, if you have `GIT_DIR` exported, you do not have a
+  worktree.  Else one level above your `$GIT_DIR` is the toplevel
+  of your worktree.
+
+Repository setup
+----------------
+
+At startup:
+
+. If the command always need a repository, call
+  `setup_git_directory()`. It will ensure you have a valid
+  repository. It will `die()` otherwise. If a worktree is detected,
+  it will be setup automatically.
+
+. If the command can optionally run in a repository, use
+  `setup_git_directory_gently(&nongit_ok)`,which is similar
+  to `setup_git_directory()` except it won't `die()`
+  but sets `nongit_ok` to true if run outside a repository.
+  No chdir(2) is done.
+
+. If you don't want worktree setup at all, but always need a git repository,
+  you can use `setup_git_directory_gently(NULL)`.
+
+Do not access git repository (even indirectly like `git_config()`) before
+calling one of these functions. Otherwise you may encounter `die()` if git
+fails to automatically find/setup a repository.
+
+Working directory setup
+-----------------------
+
+If `setup_git_directory()` is used, worktree can be optionally setup already.
+To check if work tree has been setup, use `get_git_work_tree()`. The return
+value is `NULL` if no work tree is setup or work tree directory otherwise.
+
+If you need a working directory, use `setup_work_tree()`. It will
+move current directory to top-level working directory and return
+a prefix. It will `die()` if unable to setup working directory.
+
+Miscellanous functions
+----------------------
+
+To know where `$GIT_DIR` is, use `get_git_dir()`. It will always return
+an absolute path. To know where `$GIT_WORK_TREE` is, use
+`get_git_work_tree()`. To check if you are inside a worktree or a git
+repository, use `is_inside_work_tree()` or `is_inside_git_dir()` respectively.
+There functions may be not valid until `setup_git_directory*()` is called.
+
+When working with pathspecs and prefix, you can use `get_pathspec()`
+to auto prepend a given prefix to pathspecs. Other helpful functions
+are `prefix_path()`, `prefix_filename()`
-- 
1.5.4.2.281.g28d0e